1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method for forming an image by developing a latent image formed on an image carrier by means of a liquid developer consisting of toner and carrier, transferring the developed image onto a medium such as a sheet of recording paper and fusion-bonding the transferred toner image to and fixing it on the medium.
2. Description of the Related Art
There have been proposed various wet type image forming apparatus designed to develop an electrostatic latent image to visualize the latent image by means of a highly viscous liquid developer, which is prepared by dispersing solid toner in a liquid solvent. The developer to be used for such a wet type image forming apparatus is prepared by suspending solid (toner particles) in a highly viscous organic solvent (carrier liquid) that is typically made of silicon oil, mineral oil, edible oil or the like and electrically insulating and the toner particles are very fine and have a particle size of about 1 μm. Thus, the wet type image forming apparatus can produce high quality images if compared with dry type image forming apparatus designed to employ powdery toner particles having a particle size of about 7 μm.
While the image forming apparatus designed to use a liquid developer as described above can produce high quality images, they are accompanied by problems to be dissolved. For example, the image forming apparatus designed to use a liquid developer has a problem of difficulty of controlling the liquid developer on the photosensitive member (image carrier) and many of the rollers thereof such as development rollers because the developer is liquid. More specifically, the liquid developer on such a roller may flow to the opposite end facets of the roller and/or form a liquid ring on the roller.
To cope with the problem of forming a liquid ring, JP 2007-114380-A (Patent Document 1) discloses an image carrier squeezing device for collecting surplus liquid developer. The proposed image carrier squeezing device is so designed as to be arranged at the downstream side of the nip section of an image carrier 10Y and a development roller 20Y disposed opposite to the image carrier 10Y in order to collect the surplus liquid developer from the toner image produced on the image carrier 10Y as a result of a developing process. It includes an image carrier squeezing roller 13Y that is an elastic roller member having an elastic body 13-1 as a surface coat and held in contact with the image carrier 10Y and a cleaning blade 14Y pressed against and held in contact with the image carrier squeezing roller 13Y to clean the surface of the squeezing roller 13Y. It is adapted to collect the surplus carrier C and the unnecessary fogging toner T″ from the developer D used for the developing process executed on the image carrier 10Y to raise the toner particle content ratio in the visible image.